The invention relates to techniques for performing oilfield operations relating to subterranean formations having reservoirs therein. More particularly, the invention relates to techniques for optimizing a wellbore based on a reservoir stress model, for example, determining a wellbore design parameter for a wellbore trajectory from the reservoir stress model.
Oilfield operations are typically performed to locate and gather valuable downhole fluids from a reservoir. Typical oilfield operations may involve, for example, surveying, seismic testing, drilling, wireline testing, completions, production, planning, and oilfield analysis. Drilling operations may involve drilling a wellbore, pumping a mud into the wellbore, and the like. Developing a strategy for well (or wellbore) placement, may involve an examination of the safe mud weight window for drilling the well. The safe mud weight window may be a weight of drilling mud used during drilling operation. The safe mud weight window may vary for each trajectory and may be determined for each specific well trajectory by first doing a detailed analysis of an existing drilled wellbore. From the existing wellbore, a geomechanics expert may analyze and calculate the wellbore stability for the planned wellbore. From the wellbore stability of the existing wellbore, the geomechanics expert may determine a safe mud weight window. The calculations typically used to determine the wellbore stability may be complex and may require an expert to work weeks or months processing the information for each of the formed wellbores.
Base models of reservoirs have been formed to determine risks and properties of the reservoir, such as drilling hazards, and potential hydrocarbons. Examples of base models and methods of forming base models are described in U.S. Pat. Nos. 5,982,707, 6,014,343, and 6,138,076 the entire contents of which are herein incorporated by reference.
Despite the existence of techniques for forming base models and determining a safe mud weight window for an existing wellbore, there remains a need to optimize a drilling operation quickly by determining properties for a potential trajectory. It is desirable that such techniques take into consideration the reservoir stress properties prior to completing the wellbore. It is further desirable that such techniques determine wellbore properties for one or more potential trajectories and compare the properties to optimize the wellbore(s) to be formed along the trajectories. Such techniques are preferably capable of one or more of the following, among others: reducing formation damage, minimizing sand optimizing production, reducing costs, reducing risks, reducing uncertainties, collecting data in real time, analyzing data in real time, updating operations in real time, adjusting operations in real time, providing a reliable analysis, and providing efficient data acquisition.